With wide work,the study is focused on the material components and structural characteristics ofthe red soil of different causes of formation. The major factor determining the geo- technical engineering proper-ty of the red soil is free iron oxide. Because of presence of manv free oxides of different kinds and different formsresulting in high strength of the red soil with high water content and high porosity,the standard value for thefoundation bearing capacity of the red soil can not be identified with that for the common clay. Description is alsomade on how to increase the foundation bearing capacity and determine the standard value.